"Most school's PCs spend their time idle," says Taylor. "The hardware specified is just too powerful for the tasks required of school children. They're like an SUV for every child."

The report criticises the Government target of an interactive whiteboard in every classroom and a computer for every pupil. Sirius predicts this will increase power consumption tenfold over the next decade.

"The hardware requirements to run Windows Vista means these consumption figures will rise even further," surmises Taylor.